Yesterday was an interesting day in which I found out that the untethered jailbreak solution that we have been waiting for more than a month and a half is still far from being ready for a public release, but we also found out that the Dev Team would have found an exploit which could be turned into an unlock solution only for iPhone 4S. Yes, in the image above we have a not very convincing proof of the fact that MuscleNerd would have managed to find an exploit that could lead to the development of an unlock solution dedicated exclusively to the iPhone 4S terminal but not to the iPhone 4 terminal or the 3GS .
iPhone 4S, iPhone 4 and iPhone 3GS have different baseband chips, so for each model you have to find a different exploit in the baseband and this is extremely difficult to do. Apple managed to fragment the unlock solution bringing it to the situation where the Dev Team has to triple their efforts to produce a method to decode all the iPhone models sold now and it seems that they are focusing on the most important one, the iPhone 4S . Whether or not this unlock solution will reach the hands of users in the next days/weeks/months, only the Dev Team knows, but it is certain that at the moment there is no decoding solution for iPhone 4S.
For iPhone 3GS/4, ultrasn0w can be used to decode basebands 05.13.x/06.15.00 (iPhone 3G/3GS) or lower, but also 01.59.x (iPhone 4). For iPhone 4 there is another decoding method using Gevey 3G cards, but in their case the 04.10.01 baseband is the highest that can be decoded. On iOS 5 you can decode iPhone 3GS/4 with ultrasn0w or Gevey but ONLY if you update using a custom ipsw and keep the decodable baseband intact. Tutorials that will teach you how to make a custom ipsw find here.
In conclusion, the Dev Team makes promises, it is very far from offering something viable and factory unlocked terminals are the best solution to get rid of the decoding problem.
UPDATED: ultrasn0w is not compatible with iOS 5.0.1 so do not try to install this version of iOS because you will not be able to decode.
